1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_SYNCHRONIZATION_LOCK_IMPL_H_ 6 #define BASE_SYNCHRONIZATION_LOCK_IMPL_H_ 7 8 #include "build/build_config.h" 9 10 #if defined(OS_WIN) 11 #include <windows.h> 12 #elif defined(OS_POSIX) 13 #include <pthread.h> 14 #endif 15 16 #include "base/base_export.h" 17 #include "base/basictypes.h" 18 19 namespace base { 20 namespace internal { 21 22 // This class implements the underlying platform-specific spin-lock mechanism 23 // used for the Lock class. Most users should not use LockImpl directly, but 24 // should instead use Lock. 25 class BASE_EXPORT LockImpl { 26 public: 27 #if defined(OS_WIN) 28 typedef CRITICAL_SECTION NativeHandle; 29 #elif defined(OS_POSIX) 30 typedef pthread_mutex_t NativeHandle; 31 #endif 32 33 LockImpl(); 34 ~LockImpl(); 35 36 // If the lock is not held, take it and return true. If the lock is already 37 // held by something else, immediately return false. 38 bool Try(); 39 40 // Take the lock, blocking until it is available if necessary. 41 void Lock(); 42 43 // Release the lock. This must only be called by the lock's holder: after 44 // a successful call to Try, or a call to Lock. 45 void Unlock(); 46 47 // Return the native underlying lock. 48 // TODO(awalker): refactor lock and condition variables so that this is 49 // unnecessary. 50 NativeHandle* native_handle() { return &native_handle_; } 51 52 private: 53 NativeHandle native_handle_; 54 55 DISALLOW_COPY_AND_ASSIGN(LockImpl); 56 }; 57 58 } // namespace internal 59 } // namespace base 60 61 #endif // BASE_SYNCHRONIZATION_LOCK_IMPL_H_ 62
